This mod will fix your Nikon 5000 so it will work like it was supposed to work. It will get rid of the preflash forever. It has only been tested to work on my SB-22S flash, but the fix should be similar on other Nikon Speedlights. Use an ohm meter to test which wire to cut. The fix will void your Speedlight warrantee. Due the mod at your own risk. Don't blame me if you break your Speedlight.
http://www.pbase.com/image/5383927.jpg
There are two ways to fix the preflash problem with the Nikon Speedlight flashes. One is to tape up the pin shown above with some electrical tape. This is just a temporary fix and soon your tape will fall off. The other option is to take off the bottom part of the Speedlight and cut a wire. All you do is take off those 4 phillip head screws shown on the bottom of the flash and pop off the bottom cover.
http://www.pbase.com/image/5563001.jpg
You will see a big white plug with 6 wires on it. I first unplugged the wires from the plug and used an ohm meter to see which wire was the one that led to the pin with the tape on it from the hotshoe. On my SB-22S, it was the red wire. So all I had to do was cut the red wire. This trick only works with the Nikon SB-22S flash. If you have a different flash, you have to use an ohm meter to see which wire you have to cut. It will void your flash warrantee, so do it at your own risk. As far as I can tell, everything still works like it is supposed to. The preflash is gone and the flash flashes like it normally does. You will have to upgrade your firmware on your 5000 to version 1.7 for this mod to work. You will then be able to use slave flashes without the preflash setting them off, and you can use your external Speedlight without the preflash draining your main camera battery. If anybody tries the mod on a different Speedlight and it works, let me know.
Thanks
Ralph